Method for preparing measured lengths of dental floss

ABSTRACT

A method and apparatus for preparing measured lengths of dental floss for use in dental hygiene devices which include stretching wax-coated synthetic unplasticized vinyl resin dental floss between a pair of spaced clamps, closing a grid of heat resistant bars about the stretched dental floss and applying a high-heat source to the dental floss between the bars of the grid to melt the exposed dental floss thereby forming measured lengths of dental floss with rubs at each end thereof.

R. J. ESPINOSA 3 Sheets-Sheet l INVENTOR RENE J. ESPINOSA Get. 30, 1973METHOD FOR PREPARING MEASURED LENGTHS OF DENTAL FLOSS Filed March 24,1971 Qmw g I Oct. 30, 1973 R. J. ESPINOSA 7 METHOD FOR PREPARINGMEASURED LENGIHS OI DENTAL FLOSS 3 Sheets-Sheet :3

Filed March 24. 1971 L T Y INVENTOR RENE J. ESPINOSA IMO Oct. 30,1973 R.J. ESPINOSA 3,769,396

METHC'D FOR PREPARING MEASURED LENGTHS OF DENTAL FLOSS 3 Sheets-SheetFiled March 24, 1971 INVENTOR RE NE J. ESPIN OSA WQQW; WM TTQRNEYSUnited States Patent 3,769,396 METHOD FOR PREPARING MEASURED LENGTHS 0FDENTAL FLOSS Rene Jose Espinosa, 21 S. Stone, Ave., La Grange, Ill.60525 Filed Mar. 24, 1971, Ser. No. 127,537 Int. Cl. B29c 17/14; B29d31/00 US. Cl. 264-157 1 Claim ABSTRACT OF THE DISCLOSURE A well knownsource of tooth decay is the entrapment of food particles betweenadjacent teeth. It has long been accepted dental hygiene practice toremove these particles by the use of a strip of material known as dentalfloss. Most commonly a length of floss is tensioned between the userstwo index fingers which must then be extended into the users mouth whilepositioning the floss and moving it between the teeth with a reciprocalmotion. This is at best an awkward operation and usually is wasteful inthe amount of dental floss used.

There have recently been a number of developments in the area of dentalhygiene devices which are dental floss holders designed to hold ameasured length of dental floss suflicient for cleaning ones teeth andwhich may be used with much more dexterity than with the above-mentionedcommon method. An example of such a device is described in my copendingpatent application Ser. No. 859,882 filed Sept. 22, 1969 and entitledDental Floss Holder and Floss Therefor, now Pat. No. 3,631,869. Theseholders require that the dental floss used therewith have apredetermined length and some means on the ends by which the dentalfloss can be gripped in tension. While a knot tied in the dental flosswill do, it is rather slow to prepare a length of dental floss by thismethod and the resulting length of dental floss may well be outside ofthe requirements.

There are other well known methods for treating advancing lengths ofthermal plastic filament material by haet and pressure steps. Thesemethods form crimps in the filament or roughen the surface thereof.Neither of these methods is suitable for the present use since neitherthe crimps nor roughness will provide a suflicient grip when thefilament is tensioned in the holder.

The present invention provides a uniquely simplified method andapparatus for forming measured lengths of dental floss with nubs on bothends thereof by placing continuous lengths of dental floss between pairsof heatresistant bars formed into a grid and passing heat between thespaced pairs of bars to melt the exposed dental floss thus forming alength of dental floss equal in length to the width of the bars and withnubs formed integrally on the ends thereof. Thus it is an object of thepresent invention to provide a novel measured length of dental flosshaving integral nubs on the ends thereof.

It is another object of the present invention to provide a method forforming measured lengths of dental floss with integral nubs on the endsthereof.

It is a further object of the present invention to provide a novelapparatus for producing measured lengths of dental floss, with integralnubs on the ends thereof, which may be readily and economicallyproduced.

The means for accomplishing the foregoing objects and other advantages,which will be apparent to those skilled in the art, are set forth in thefollowing specification and claim and are illustrated in theaccompanying drawings dealing with a basic embodiment of the presentinvention. Reference is now made to the drawings in which:

'FIG. 1 is a perspective view of a length of dental floss and anappropriate holder;

FIG. 2 is a perspective view of one form of the apparatus suitable forperforming the inventive method;

FIG. 3 is a plan view of the apparatus shown in FIG. 2;

.FIG. 4 is a longitudinal section taken along line 4-4 of FIG. 3 and asuitable heat source means;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 3;

FIG. 6 is a detailed vertical sectional view showing one length ofdental floss between the closed bars of the grid.

Before discussing the particular inventive method and apparatus, itshould be noted that while dental floss is made of a number of dilferentmaterials, such as natural silk fibers, the present invention isintended to be used with dental floss o-f unplasticized vinyl resindescribed by Pat. No. 2,381,142 to Stonehill, issued Aug. 7, 1945.

Turning now to the figures, the holder illustrated in FIG. 1 is of thetype described in my copending application Ser. No. 859,882. The holder10 has a handle portion 11 and a pair of parallel prongs 12 and 13extending from one end of the handle portion. Slots 14 and 15 areprovided in the free ends of prongs 12 and 13, respectively. Themeasured length of dental floss 16 has nubs 17 and 18 integrally formedon the ends thereof. The distance between the outer edges of the prongsis substantially equal to the distance between the nubs when the dentalfloss is tensioned. The measured length of dental floss is placed in theslots 14 and 16 with the nubs 17 and 18 on the outer sides of the prongs12 and 13, respectively. Means can be provided to further tension thedental floss between the prongs after mounting. The advantages of thisarrangement are aptly described in my previouslymentioned copendingpatent application Ser. No. 859,882.

The FIG. 2 shows an exemplary embodiment of the apparatus for carryingout the inventive method.

The apparatus comprises a frame 19 having depending legs 20 and can begenerally divided into two portions, namely, a feed portion 21 and atreating portion 22. The feeding portion 21 of the frame 19 has aplurality of vertically extending pins 23 on which are mounted aplurality of bobbins 24 each holding a length of dental floss 25. Thefeed portion is also provided with a comb-like device 26 which isfixedly mounted on the frame 19 with its teeth extending verticallyupwardly for separating the individual strands of floss as they are fedfrom the individual bobbins.

The treatment portion 22 of the frame 19 has removable clamps 27 at eachend thereof and normally arranged to be substantially parallel to eachother.

Each clamp is formed by two bars 28 and 29 of heat insulating materialwith magnets 30, 31, 32 and 33 at the ends thereof. The magnets serve atwo-fold purpose in that they hold the clamp bars together and they holdthe clamps 27 in place on the frame 19 when the dental floss istensioned.

Between the spaced clamps 27 there is a grid member 34 formed by upper35 and lower 36 matching sets of parallel heat resistant bars 37. Thelower set of bars 36 is fixedly mounted on the frame 19. The upper setof bars has cross members 38 and 39 at the ends thereof fixing the barsin parallel spaced relationship. The upper and lower sets of bars arehinged together on one side by hinge means 40. A rest member 41 isprovided secured to the frame 19 and positioned to receive and hold theupper set of bars 35 in the open position. The apparatus is completed bythe heat source 42 which has here been shown as an arrangement of gasjets 43 positioned below the frame 19 and fed from a gas supply 44through the means of flexible hose 49. The heat source 42 is preferablyarranged on a table 50 arranged between the legs 20 and provided with apair of spaced parallel guides 51. As can best be seen in FIG. 5, theheat source 42 can be provided with either manual or automatic means(not shown) for sliding the heat source transversely across the width ofthe apparatus so that the individual strands of dental floss are severedbetween the bars 37 and the integral nubs are formed. This arrangementallows for an economical and simplified heat source structure since eachgas jet 43 is positioned close to the dental floss.

The operation of the device is as follows: a plurality of bobbins 24 aremounted on the pins 23 and the dental floss 25 thereon is initiallythreaded through the comblike device 26 and across the open clamps 27and grid member 34. The free ends of the dental floss are secured firstby closing one clamp 27. The opposite end of the dental floss, the sideadjacent the comb-like member, is pulled to place the dental floss undera slight tension and clamped by the other clamp 27. The grid member 34is then closed by lowering the upper set of bars 36 so that a number oflengths of dental floss are held in a heat insulated condition betweenthe sets of bars. While it is preferable that the spacing between eachclamp 27 and the adjacent bar of the grid member be equal to the spacingbetween the bars, this is not an essential requirement. Marking guidescould be placed on the frame or the end gas jets could be made larger tocompensate for the additional length of dental floss. However, since thepositioning of the clamps is for the purpose of tensioning the dentalfloss, some allowance for spacing variation should be made. The gas jetsare then ignited and the heat source 42 is moved across the table 50 toheat and melt the exposed dental floss between the adjacent closed pairsof heat insulated bars thus forming the configuration of the dentalfloss as shown in FIG. 6, namely, a measured length of dental floss 45with integral nubs 46 and 47.

Upon completion of the melting process, the gas jets are turned off, theupper set of bars 35 is raised, and the completed severed lengths ofdental floss having nubs on either end are removed from the lower set ofbars 36, preferably by a rake-like device or other suitable means notshown.

Subsequent operations of the apparatus are similar to theabove-described initial operation. However, nubs will be formed at thefree ends of the dental floss at the clamp 27 nearest the comb-likemember 26. Since both clamps 27 are held together and on the frame 19only by their magnets 30 to 33, the apparatus can be restranded merelyby opening the grid member 34 and moving the clamp 27 nearest thecomb-like member 26 to the far side of the grid member 34, to the rightin FIGS. 2, 3 and 4. The nubs 48, see FIG. 4, on the free ends of thedental floss 25 will not slip between the bars 28 and 29 of the clamp 27so that the dental floss will again be positioned. The other clamp 27can be opened to remove the completely formed measured lengths heldtherein and clamped around the dental floss adjacent the comb-likemember 26. The clamps are preferably but not necessarily spaced from thegrid member by a distance substantially equal to the spacing between thebars of the grid member. The grid member 34 can be closed and the heatoperation repeated.

It should be noted that the bars 28 and 29 of the clamps 27 are of equalwidth as the bars 37 of the grid member 34 and are preferably of thesame heat resistant material. This allows the formation of an extra setof measured lengths of dental floss for each operation of the device, atotal of 56 in the apparatus illustrated.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Thepresent embodiment is therefore to be considered in all respect asillustrative and not restrictive, the scope of the invention beingindicated by the appended claim rather than the foregoing descriptionand all changes which come within the meaning and range of equivalencyof the claim are therefore to be embraced therein.

I claim: 1. A method for producing precise predetermined equal lengthsof dental floss which lengths terminate in integral nubs at each endthereof, comprising:

tensioning a span of floss composed of synthetic unplasticized vinylresin material between spaced apart pairs of mating blocks of heatresistant material,

clamping portions of said tensioned span of said material between pairsof mating blocks of heat resistant material which pairs are spaced fromadjacent pairs, the width of said pairs being equal to theaforementioned predetermined .length and applying heat to the unclampedportions of said tensioned span to sever said span by melting saidunclamped portions up to the surfaces of said mating blocks whichprevent any further spread of the melting and creating nubs on the endsof a plurality of said thus formed lengths of dental floss.

References Cited UNITED STATES PATENTS 2,702,555 2/1955 De Mar 264- X3,574,804 4/1971 Joonase 264--80 3,092,439 6/1963 Harrison 264-230 X3,392,070 7/1968 Gropp 264-163 X 3,270,408 9/1966 Nealis 264-230 X3,157,721 11/1964 Barish 264-157 2,702,556 2/1955 De Mar 264-80 X3,673,301 6/1972 Billarant 264-163 ROBERT F. WHITE, Primary Examiner A.M. SOKAL, Assistant Examiner US. Cl. X.R. 264-80, 163

